Abstract

A 36 year old man developed slowly progressive unilateral visual loss due to a cystic lesion of the intraorbital optic nerve. Pathologically the lesion was an epithelium lined cyst entirely within the atrophic nerve. The cyst lining consisted of columnar epithelium partly pseudostratified and ciliated with evidence of mucin secretion, and was immunoactive for cytokeratin but not glial fibrillary acidic protein. This lesion is considered to be similar to neuroenteric cysts that have been reported elsewhere in the nervous system, and the immunocytochemical results are consistent with a heterotopia derived from the primitive ectoderm of the stomatodeum.